The present invention relates to a portable automatic apparatus for assembling frame structures from standard raw materials, and particularly to portable apparatus for constructing stud frame walls.
In the building construction industry the construction of stud frame walls, that is, the "framing" of a building, is typically a highly labor intensive activity and is therefore very expensive. Such stud frame walls are conventionally made by fastening a plurality of elongate wooden studs in vertical orientation and parallel to one another at predetermined intervals longitudinally between and perpendicular to a pair of elongate horizontally-disposed wooden plate members. The frame thus assembled and fastened together, if for an outside wall, is then covered on at least one side by sheathing, usually plywood sheets which are nailed to the frame. Ordinarily, the apertures for doors, windows, and the like are formed by precutting the parts of the wall frame prior to assembly.
These steps ordinarily require the efforts of a number of individual laborers at the building site and are performed at different times. It has been found, however, that the expense of the framing can be considerably reduced by applying mass production techniques to produce prefabricated walls which may be erected at the building site in partially finished form and that the cost can be further reduced and the quality increased by the use of automatic machinery to produce the walls.
In the past, prefabricated wall sections have commonly been manufactured at a location remote from the site of the building in which they are to be incorporated. Remote construction of walls, however, presents risks of damage in handling and transit to the construction site, which may require expensive on-site repairs. Additionally, transportation of such prefabricated sections creates only low-density loading of trucks and the like carrying such wall sections. These consequences of remote prefabrication lead to cost inefficiency of construction and point to the desirability of on-site automatic wall section fabrication.
Several apparatus have previously been invented which attempt to accomplish effectively the results of automatically, or semi-automatically, manufacturing prefabricated wall frames. For example, Hurn, et al, U.S. Pat. No. 3,564,702 discloses a type of apparatus for assembling part of a wall frame, but it is quite complex and does not show any specific mechanism for feeding those parts to the assembly apparatus or for completing the wall by adding sheathing and cutting holes for windows, doors, or conduits. Kellner, et al, U.S. Pat. No. 3,851,384 also shows an apparatus for manufacturing a prefabricated building wall, but is even more complex, requiring a very complicated mechanism for assembling the parts of the wall. Similarly, Bamford, Sr., U.S. Pat. No. 2,574,163 discloses an apparatus for assembling a building wall, but it utilizes complex moving mechanisms for distributing the parts of a wall over an assembly table, and requires that some of those parts be individually prefabricated. Jureit, et al, U.S. Pat. No. 3,685,129 and Carroll, U.S. Pat. No. 3,399,445 also disclose apparatus of this general type.
Schultz U.S. Pat. No. 4,039,112 discloses apparatus for construction of frame structures in which a reciprocating mechanism selects individual studs, places them individually between a pair of plate members, and automatically nails the studs in place. Provision is made for attaching sheathing material and for cutting away portions of the wall section to form apertures for doors, windows, and the like. The apparatus disclosed by Schultz, however, is neither portable nor adjustable for construction of walls of different heights or from different sizes of lumber.
There remains, therefore, a need for an improved and more efficient highway-transportable apparatus operable with normally available power to quickly and accurately build sheathed wall sections of various heights and thicknesses at the site of building construction.